Electron microscope image contrast from multiple Frank dislocation loops

Abstract

The image contrast from multiple Frank dislocation loops in quenched aluminum and dilute aluminum–magnesium alloys has been investigated systematically using transmission electron microscopy. From detailed examinations of fully faulted and partially unfaulted triple loop configurations, self-consistent dislocation reactions have been derived. Changes in image contrast due to partial unfaulting of multiple loops has been discussed in terms of possible defect models. It has been concluded that unless an assumption regarding the effects of dislocation–core interactions is made, a distinction between these defect models is not possible from the present observations.